1. Field of the Invention
The present invention relates to an airbag used for a top-mount type airbag device for front passenger's seat, which is mountable on top face side of instrument panel (as will be called “dashboard”) in front of front passenger's seat.
2. Description of Related Art
In the prior art, Japanese Patent Laid-Open No. 2003-335203, in FIGS. 17 to 28, discloses an airbag for front passenger's seat. This airbag includes: a gas inlet port for introducing inflation gas in the vicinity of front end thereof as completely inflated; and a protection portion adapted to be thrown against a passenger seated in front passenger's seat, in a rear side thereof as completely inflated. The protection portion includes two inflatable portions which are disposed side by side in left-right direction, and communicated with each other in the vicinity of the gas inlet port. In this airbag for front passenger's seat, the two inflatable portions are joined by a joint panel proximate to rear ends thereof. The joint panel is arranged along left-right direction and is adapted to receive and protect the passenger.
In the airbag for front passenger's seat in the prior art, however, since the joint panel for receiving a passenger is formed into a generally planar shape upon airbag deployment, there is a room for improvement in properly protecting the passenger while suppressing a reaction force applied to the passenger, when the joint panel is thrown against the passenger upon airbag inflation. Especially, in order to protect the passenger, there is a challenge in suppressing a reaction force applied to a passenger's head that is small in mass.
In the meantime, in the airbag for front passenger's seat in the prior art, the two inflatable portions constituting the protection portion are communicated with each other only in a small area in the vicinity of the gas inlet port. With this construction, it is difficult for the two inflatable portions to be inflated uniformly when the protection portion inflates with inflation gas from an inflator, which may slant the joint panel, and may lead to failure in protecting the passenger properly.